I am interested in purchasing a 223 rifle for self-defense, but have some reservations about buying an AR15 type carbine. It seems as though there are so many maintenance problems with dirty pistons/chambers and broken firing pins with the AR type. The bolt action rifles seem more reliable, and I already have 3 (22 mag, 270, & 303). What are your thoughts on having a good quality 223 rifle equipped with a scope? My Ruger PC 4 in 40 caliber is great, but it is somewhat limited in effective range. Thank you for your comments.